U.S. patent application number 14/438371 was filed with the patent office on 2015-10-08 for motor-driven hinge device for vehicle seat hinge.
This patent application is currently assigned to FAURECIA SIEGES D'AUTOMOBILE. The applicant listed for this patent is FAURECIA SI GES D'AUTOMOBILE. Invention is credited to Naoufel Boutouil, Nicolas Navatte.
Application Number | 20150283924 14/438371 |
Document ID | / |
Family ID | 47624305 |
Filed Date | 2015-10-08 |
United States Patent
Application |
20150283924 |
Kind Code |
A1 |
Boutouil; Naoufel ; et
al. |
October 8, 2015 |
MOTOR-DRIVEN HINGE DEVICE FOR VEHICLE SEAT HINGE
Abstract
Motor-driven hinge device comprising a hypocycloid hinge
mechanism (7) driven by a drive shaft (8), comprising two metal
side plates (71,72) intended for connection to the seating portion
(11) and to the backrest (12), a brushless motor (20), and a
planetary gear train (30) positioned between the brushless motor
(20) and the drive shaft (8), the planetary gear train comprising a
sun gear (6) connected to the motor rotor, and a plurality of
planet gears (3), each planet gear comprising: a first set of teeth
(31) engaging with the sun gear (6) and with a first stationary
ring gear (4), and a second set of teeth (32) engaging with a
second ring gear (5) rigid with to the drive shaft (8).
Inventors: |
Boutouil; Naoufel; (Flers,
FR) ; Navatte; Nicolas; (Laisney, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FAURECIA SI GES D'AUTOMOBILE |
Nanterre |
|
FR |
|
|
Assignee: |
FAURECIA SIEGES
D'AUTOMOBILE
NANTERRE
FR
|
Family ID: |
47624305 |
Appl. No.: |
14/438371 |
Filed: |
October 9, 2013 |
PCT Filed: |
October 9, 2013 |
PCT NO: |
PCT/FR2013/052405 |
371 Date: |
April 24, 2015 |
Current U.S.
Class: |
297/362 ;
16/354 |
Current CPC
Class: |
B60N 2/2252 20130101;
Y10T 16/541 20150115; B60N 2/0232 20130101; B60N 2002/0236
20130101; F16C 11/04 20130101; B60N 2/2251 20130101 |
International
Class: |
B60N 2/02 20060101
B60N002/02; B60N 2/225 20060101 B60N002/225; F16C 11/04 20060101
F16C011/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 26, 2012 |
FR |
12 60249 |
Claims
1. A motor-driven hinge device adapted to connect a backrest of a
motor vehicle seat to a seating portion of said seat, in a
rotational movement about a hinge axis, comprising: a first
hypocycloid hinge mechanism driven by a drive shaft, comprising a
first metal side plate for connection to the seating portion and a
second metal side plate for connection to the backrest, the first
and second side plates being connected by metal toothed sectors, a
brushless motor having a rotor rotating about a rotor axis parallel
to the hinge axis, a planetary gear train interposed between the
brushless motor and the drive shaft, the planetary gear train
comprising a sun gear rotating about a main axis and connected to
the motor rotor, a plurality of planet gears, each planet gear
comprising: a first set of teeth engaging with the sun gear and
with a first stationary ring gear, and a second set of teeth
engaging with a second ring gear rigid with the drive shaft,
wherein the planetary gear train has no planet carrier.
2. The motor-driven hinge device according to claim 1, wherein all
parts of the planetary gear train are made of plastic.
3. The motor-driven hinge device according to claim 1, further
comprising a control unit arranged in immediate proximity to the
brushless motor, for controlling said brushless motor; said
brushless motor, the planetary gear train, and the control unit
being contained in a closed housing.
4. The motor-driven hinge device according to claim 1, wherein the
first set of teeth and the second set of teeth differ in their
number of teeth by 1, and/or the number of teeth of the first ring
gear differs from the number of teeth of the second ring gear.
5. The motor-driven hinge device according to claim 1, wherein the
reduction ratio of the planetary gear train is between 50 and 150
and the rotational speed of the motor is between 2000
revolutions/min and 7000 revolutions/min.
6. The motor-driven hinge device according to claim 1, wherein the
planetary gear train and the brushless motor are arranged one
beside the other in a plane perpendicular to the main axis, and are
interconnected by a belt.
7. The motor-driven hinge device according to claim 1, wherein the
planetary gear train and the brushless motor are arranged one after
the other in the axial direction.
8. A seat frame for a motor vehicle, comprising a backrest frame, a
seating portion frame, and at least one motor-driven hinge device
according to claim 1.
9. The seat frame according to claim 8, comprising a second
hypocycloid hinge mechanism arranged on the side opposite to the
first hypocycloid hinge mechanism, the drive shaft passing axially
through the planetary gear train and connecting the two hypocycloid
hinge mechanisms.
10. A motor vehicle seat comprising at least one motor-driven hinge
device according to claim 1.
Description
[0001] The present invention relates to motor-driven hinge devices
with electric motor and reduction gear, arranged to drive an
element of a motor vehicle seat, for example to move a movable
element relative to a reference element, for example a backrest
relative to a seating part.
[0002] In the known prior art, many motor-driven hinge devices make
use of a gearmotor, which comprises a brushless or DC motor and one
or more gear stages for moving a movable element substantially in
rotation relative to a reference element.
[0003] These motor-driven hinge devices must satisfy multiple
constraints, the main ones being silent operation, maintaining
position in the event of impact, reliability, small footprint,
performance, and ease of integration.
[0004] According to document U.S. Pat. No. 7,544,142, a brushless
single or double motor can be used, to which is added a complex
differential gear, making the device expensive and possibly
insufficiently resistant to impacts.
[0005] There is therefore a need for motor-driven hinge devices
with electric motor and reduction gear (referred to as a
"gearmotor") of simplified construction, sized to optimize their
installation, particularly within a confined space of a vehicle
seat, and which also help reduce noise from the operation of such
gearmotors, achieving all this without decreasing the impact
resistance of such hinge devices.
[0006] The present invention proposes a motor-driven hinge device
that is adapted to connect a backrest of a motor vehicle seat to a
seating portion of said seat, in a rotational movement about a main
axis, comprising: [0007] a first hypocycloid hinge mechanism driven
by a drive shaft, comprising a first metal side plate for
connection to the seating portion and a second metal side plate for
connection to the backrest, the first and second side plates being
connected by metal toothed sectors, [0008] a brushless motor having
a rotor rotating about a rotor axis parallel to the main axis,
[0009] a planetary gear train interposed between the brushless
motor and the drive shaft, the planetary gear train comprising a
sun gear rotating about the main axis and connected to the motor
rotor, a plurality of planet gears each comprising a first set of
teeth engaging with both the sun gear and a first stationary ring
gear, and a second set of teeth engaging with a second ring gear
rigid with the drive shaft,
[0010] wherein the planetary gear train has no planet carrier.
[0011] With these arrangements, the architecture of such mechanisms
can be simplified, and the operational noise and size of such
mechanisms can be optimized to facilitate their installation and
integration into the passenger compartment of motor vehicles, while
maintaining good impact resistance and satisfactory performance. In
addition, the assembly of such a mechanism is simplified.
[0012] In various embodiments of the invention, one or more of the
following arrangements may possibly be used, individually or in
combination: [0013] all parts of the planetary gear train are made
of plastic; thus optimizing the cost of the device; [0014] the
device may further comprise a control unit arranged in immediate
proximity to the brushless motor, for controlling said brushless
motor, said brushless motor, the planetary gear train, and the
control unit being contained in a closed casing; such that the
device provides good reduction of electromagnetic emissions and the
control unit is protected from external physical and chemical
damage; [0015] the first set of teeth and the second set of teeth
differ in their number of teeth by 1, and/or the number of teeth of
the first ring gear differs from the number of teeth of the second
ring gear; such that a reduction ratio of between 50 and 150 can be
obtained for the planetary gear train; [0016] the reduction ratio
of the planetary gear train is between 50 and 150 and the
rotational speed of the motor is between 2000 revolutions/min and
7000 revolutions/min; such that a brushless motor of reduced
dimensions can be selected; [0017] the reduction gear train and the
motor can be arranged one beside the other in a plane perpendicular
to the main axis, and are interconnected by a belt; such that the
occupied volume is reduced axially; [0018] the planetary gear train
and the brushless motor can be arranged one after the other in the
axial direction; such that the occupied volume is reduced radially;
[0019] the device may further comprise an intermediate planetary
gear set interposed axially between the brushless motor and the
planetary gear train; such that the performance of each gear stage
can be optimized; [0020] the control unit is arranged to control
the motor according to current output profiles with startup and
shutdown ramps; to obtain smooth starts and stops.
[0021] The invention also relates to a seat frame for a motor
vehicle, comprising a backrest frame, a seating portion frame, and
at least one motor-driven hinge device as described above.
[0022] The motor-driven hinge device may further comprise a second
hypocycloid hinge mechanism arranged on the side opposite to the
first hypocycloid hinge mechanism, the drive shaft passing axially
through the planetary gear train and connecting the two hypocycloid
hinge mechanisms.
[0023] The invention also relates to a motor vehicle seat
comprising at least one drive device as described above.
[0024] Other features, objects, and advantages of the invention
will become apparent from reading the following description of two
of its embodiments, given as non-limiting examples with reference
to the accompanying drawings, in which:
[0025] FIG. 1 is a perspective view of a seat frame incorporating a
motor-driven hinge device according to a first embodiment of the
invention,
[0026] FIG. 2 is an exploded view of the drive device of FIG. 1,
viewed from one side,
[0027] FIG. 3 is an exploded view of the drive device of FIG. 1,
viewed from the opposite side,
[0028] FIG. 4 is a schematic axial section diagram of the
motor-driven hinge device of FIG. 1,
[0029] FIG. 5 is a transverse section view of the reduction gear of
the drive device of FIG. 1, along line VV of FIG. 4,
[0030] FIG. 6 is a transverse section view of the reduction gear of
the drive device of FIG. 1, along line VI-VI of FIG. 4,
[0031] FIG. 7 is a perspective view of a seat frame incorporating a
motor-driven hinge device according to a second embodiment of the
invention,
[0032] FIG. 8 is a schematic axial section diagram of the
motor-driven hinge device of FIG. 7,
[0033] FIG. 9 is an exploded view of the drive device of FIG. 7,
viewed from one side,
[0034] FIG. 10 is an exploded view of the drive device of FIG. 7,
viewed from the opposite side,
[0035] FIG. 11 represents a variant of the motor-driven hinge
device of FIG. 7.
[0036] In the various figures, the same references designate
identical or similar elements.
[0037] FIG. 1 represents a perspective view of a seat frame
incorporating a motor-driven hinge device 1, also referred to for
simplicity as a "motorized hinge device" 1, according to a first
embodiment of the invention. Such a frame is covered with padding
and a covering (not shown) to constitute the vehicle seat.
[0038] As illustrated in FIG. 1, the motor-driven hinge device 1
allows rotating the backrest relative to the seating portion in
order to adjust the angular position for user comfort; however, the
motor-driven hinge device must maintain the current position the
rest of the time, including in the event of vehicle impact.
[0039] The frame in question comprises a seating portion structure
11 and a backrest structure 12 mounted so as to rotate on the
seating portion structure 11 about a main hinge axis Y. In the
hinge area, the frame comprises a first hinge mechanism 7 on the
right side of the seat (indicated by dotted lines in FIG. 1) and a
second hinge mechanism 7' (partially visible) on the left side of
the seat.
[0040] The seating portion structure 11 may further comprise a
seating portion side plate 11A on each side, attached to and facing
one of the hinge mechanisms 7,7', and the backrest structure 12 may
similarly comprise a backrest side plate 12A on each side, attached
to and facing one of the hinge mechanisms 7,7'. Note that the
backrest structure 12 may be hinged on the backrest side plate 12A
in the case of a function where rear seat access is provided.
[0041] As illustrated in FIGS. 1 to 6, in the example shown, each
hinge mechanism 7,7' is a hypocycloid reduction gear mechanism as
known for seat hinges of the prior art and described for example in
document FR2962385.
[0042] Each hinge mechanism 7 (respectively 7') comprises a first
metal side plate 71 to be connected to the seating portion 11,
directly or via the seating portion side plate 11A, and a second
metal side plate 72 to be directly connected to the backrest 12 via
the backrest side plate 12A.
[0043] In a known manner, the first and second side plates 71,72
are connected, directly or indirectly, by toothed sectors. In the
example illustrated, a radially external set of teeth 76 of the
first side plate engages with a radially internal set of teeth 75
of larger diameter of the second side plate, the first side plate
71 being rotated about Y with slight nutation due to an eccentric
cam 73. The radially internal set of teeth 75 has one tooth more
than the radially external set of teeth 76 of the second side
plate. Further details on the structure and construction are given
for example in document FR2962385, keeping in mind that FIGS. 4, 8
and 11 only schematically represent the hinge mechanism 7.
[0044] When the eccentric cam 73 completes a revolution, the teeth
76 of the first side plate 71 are angularly offset by one tooth
relative to the teeth 75 of the second side plate 72.
[0045] A reduction of 1/N is thus obtained, where N is the number
of teeth in the set of teeth of the first side plate. The first and
second side plates are made by stamping or fine-blanking steel
material, in order to support the torques applied between the
backrest and seating portion, particularly during vehicle impact.
The number of teeth will be, for example, 35 and 36. The teeth
75,76 are metal and are preferably formed integrally with the first
and second side plates 71,72 respectively. The mechanical coupling
between the first and second side plates thus gives the hinge
irreversibility of movement and sufficient robustness to meet the
increasingly restrictive criteria for impact resistance.
[0046] The eccentric cam 73 is rotated by a drive shaft 8, which
passes through the seat frame from left to right in the example
illustrated, in a manner that connects the two hinge mechanisms
7,7'.
[0047] It should be noted that in a simplified example not shown,
the seat frame may have only one hinge mechanism 7, in which case
the drive shaft 8 would be much shorter and would locally link the
gearmotor, described below, with the single hinge mechanism 7.
[0048] The gearmotor 10 of the motor-driven hinge device 1 is
housed in a casing 19 and comprises: [0049] a brushless motor 20
having a rotor 2 rotating about a rotor axis Y2 parallel to the
main axis Y, [0050] a planetary gear train 30 interposed between
the brushless motor 20 and the drive shaft 8, the planetary gear
train 30 comprising a drive member 6, a plurality of planet gears
3, and ring gears 4 and 5 which will be detailed below.
[0051] Each planet gear 3 comprises a first set of teeth 31
engaging with both the sun gear 61 of the drive member 6 and with a
first stationary ring gear 4, and a second set of teeth 32 engaging
with a second ring gear 5 rotationally rigid with the drive shaft
8. Each planet gear 3 also has a circular outer bearing surface 33.
It should be noted that this type of planetary gear train is
sometimes called a `Wolfrom` system.
[0052] The second ring gear 5 is part of a driven gear 50 also
called the follower 50, comprising a disc portion 52, an annular
portion on the periphery of the disc portion with the teeth of said
second ring gear 5, and a cylindrical inner bearing surface 53. The
driven gear 50 also comprises a cylindrical hub 51 with a central
axial through-hole for receiving the drive shaft 8.
[0053] The planet gears 3 are held in place radially by their
circular outer bearing surface 33 which presses against both the
cylindrical inner bearing surface 53 and the outside of the hub 51
(FIG. 6).
[0054] The first ring gear 4 is part of a stationary flat ring 40
which comprises radial indentations 41 that are received in
complementary shapes provided inside the casing 19 (FIG. 6).
[0055] The rotor 2 of the brushless motor 20 may be in the form of
a substantially flat disc perpendicular to the axis of rotation Y2.
As is known per se, the rotor disc is equipped with permanent
magnets; facing them are the coils of electromagnets controlled by
a control unit 9 arranged in immediate proximity to the brushless
motor 20. The current flowing in each coil is controlled to
generate a rotating magnetic field capable of imparting rotational
movement to the rotor. The rotational speed of the rotating field
can be controlled by the control unit 9. Typically, rotational
speeds of between 2000 revolutions per minute (2000 rpm) and 7000
revolutions per minute (7000 rpm) will be chosen, and preferably
between 2000 rpm and 4000 rpm.
[0056] The rotor 2 is rotatably connected to a driven gear 22 which
is coupled to a driving gear 66 of the planetary gear train 30.
[0057] The coupling between the driven gear 22 of the motor and the
driving gear 66 of the planetary gear train may be implemented as a
transmission belt 60, as shown in FIGS. 2 and 3, for example a belt
made of elastomeric material, for example a toothed belt;
alternatively, as represented in FIG. 4, it may be a direct
engagement of one gear with the other.
[0058] According to the invention, driven gear 50 is implemented as
a single piece made of molded plastic.
[0059] In addition, advantageously according to the invention, all
parts of the planetary gear train may be made of plastic. In
another advantageous and optional aspect, the planetary gear train
has no planet carrier. In another advantageous and optional aspect,
the planetary gear train is without ball bearings or roller
bearings.
[0060] In the example shown, the brushless motor 20, the planetary
gear train 30, and the control unit 9 are contained in the closed
casing 19.
[0061] More specifically, the casing 19 is formed as a protective
housing in the form of two half-casings 19a, 19b assembled together
by attachment means such as snap-fitting means 19c, 19d. This
casing protects the internal components of the device 1,
particularly the motor 20, the reduction gear 30, and the control
unit 9, from the outside environment.
[0062] In addition, within this casing 19 are provided a first
thrust bearing 55 and a second thrust bearing 56 to support the
rotational movement of the driven gear 50. Similarly, the casing
may additionally comprise bearings for the motor rotor.
[0063] The motor-driven hinge device 1 also comprises an electrical
connector 16 provided for supplying electric power and signals to
the motor 20.
[0064] In general, a reduction ratio of between 50 and 150 is
selected for the planetary gear train.
[0065] This can be achieved by having a different number of teeth
on the first and second rings 4,5 and/or a different number of
teeth in the first and second sets of teeth 31,32 of the planet
gears 3.
[0066] The general formula for the reduction ratio of the planetary
gear train can be written as follows:
R = 1 + Z 4 Z 61 1 - Z 32 Z 4 Z 31 Z 5 ##EQU00001##
[0067] where Z.sub.61 is the number of teeth on the sun gear 61,
Z.sub.31 and Z.sub.32 are respectively the number of teeth in the
first set of teeth 31 and in the second set of teeth 32 of the
planet gears, Z.sub.4 is the number of teeth on the first ring
(stationary), and Z.sub.5 is the number of teeth on the second ring
5 (driven).
[0068] In the illustrated example the two characteristics are
combined, with Z.sub.61=15, Z.sub.31=8, Z.sub.32=9, Z.sub.4=31, and
Z.sub.5=33, to obtain R=54.
[0069] If Z.sub.31=8, Z.sub.32=8, Z.sub.4=31, and Z.sub.5=32, R=98
is obtained, with reversal of the direction of rotation.
[0070] These choices allow obtaining a very favorable reduction
ratio for the planetary gear train with satisfactory performance
and an optimal rotational speed as mentioned above for the
motor.
[0071] The reader will understand that the belt drive 60
additionally introduces a reduction factor that is typically
between 2 and 3 depending on the respective diameters of the driven
gear 22 and the driving gear 66 of the reduction gear train.
[0072] According to the first embodiment, the reduction gear and
the brushless motor 20 are arranged next to each other
substantially in a plane perpendicular to the main axis Y, and are
interconnected by the belt 60. A configuration is thus obtained
that is referred to as "flat", meaning an advantageous dimension
along the Y axis, for example less than 40 mm, and the device can
be installed on the inner side against the backrest side plate
12.
[0073] The drive shaft 8, here of square cross-section, is coupled
to the central hub 51 by their complementary shapes, is in the form
of a shaft 8 connecting the hypocycloid hinge mechanism 7 of the
right side to the hypocycloid hinge mechanism 7' of the left side,
passing from one side to the other of the reduction gear 30 inside
the hub 51.
[0074] The control unit 9 is configured to control the current in
each coil and to monitor the proper operation of the brushless
motor, and can manage a plurality of additional functions such as
managing saved positions, compensating for variations in supply
voltage, assisting with diagnostics, etc.
[0075] In particular, the control unit 9 may control the motor
according to current delivery profiles with startup and shutdown
ramps, to provide smooth starts and stops. This also limits the
emission of electromagnetic interference associated with startup
and shutdown transitions.
[0076] According to a second embodiment, represented in FIGS. 7 to
11, the reduction gear 30 and the brushless motor 20 are arranged
coaxially, end to end, the axis of the rotor Y2 coinciding with the
main axis Y. This provides a configuration referred to as "axial
cylindrical", meaning it has an advantageous radial dimension, for
example a diameter of less than 6 cm, and the device can be
installed on the inner side against the backrest side plate 12, as
illustrated in FIG. 7.
[0077] In this second embodiment, only the elements that differ
from those of the first embodiment will be discussed, as the others
are considered to be similar or identical.
[0078] In this configuration, the rotor 2 and the drive member 6
are directly coupled; alternatively they may be a single part. The
stator and rotor 2 of the motor comprise an axial through-hole
allowing the passage of the drive shaft 8 which traverses the
gearmotor 10.
[0079] According to the variant shown in FIG. 11, an additional
planetary gear train is inserted to facilitate the outputs of the
different gear stages; in this configuration, the motor rotor is
connected to the sun gear 90,91 of the additional gear train, which
drives the planet gears 92 supported by a planet carrier 6 which
forms the driving gear 61 of the main planetary gear train 30. An
outer ring 93 is arranged in a fixed manner, possibly combined with
the abovementioned stationary ring 40. The other elements relating
to the variant of FIG. 11 are not described again here because they
are identical or similar to those previously described.
[0080] To give an example, if the motor is used at 7000 rpm with a
reduction ratio of 100 in the planetary gear train, we obtain 70
rpm as input to the hinge mechanism 7 which introduces a reduction
factor of 35; in which case a rotation of 2 rpm is obtained for the
backrest (12 degrees per second). With an additional planetary gear
train (FIG. 11), the speed can be reduced to less than 1 rpm, as
can also be obtained with the belt drive of the first
embodiment.
[0081] It should be noted that according to the invention, the
motor-driven hinge device 1 can be arranged to move, within a motor
vehicle, any movable element mounted to be movable relative to a
reference element, by means of a hinge device interposed between
the movable element and the reference element.
* * * * *